6.2.3—The elastic potential energy of a material deformed within its limit of

A material deformed within its elastic limit stores elastic potential energy, equal to the work done in deforming it.

The energy is recoverable when the load is removed. Use the loading force–extension relationship rather than assuming all deformation energy is retained.

A stretched spring can return to its original length while releasing its stored elastic energy to a moving mass.

Elastic potential energy is not the same as gravitational potential energy, and plastic deformation can dissipate some input energy.